Magnetic system



March 26, 1935. P. s. EDWARDS 1,995,449

MAGNETIC SYSTEM Filed March 13, 1934 INVENTOR BY 7 f g Al IORNEY Patented Mar. 26, 1935 UNITED STATES PATENT OFFICE MAGNETIC SYSTEM Paul Griffith Edwards, Verona, N. J., assignor to American Telephone and Telegraph Company, a corporation of New York Application March 13, 1934, Serial No. 715,353

1 Claim. (Cl. 175-339) This invention relates to magnetic systems establishes magnetic paths which will be presently which are particularly adapted for use in condescribed. nection with relays, phonograph reproducers, light An armature 11 of magnetic material is carried valves, and the like. by an arm 12. This arm may be made if desired 5 One of the objects of the invention is to provide from non-magnetic material and is suitably se- 5 a magnetic system of high sensitivity. cured to the closed end of the permanent magnet 5, Another object is to provide simple adjustable and said armature is adapted to vibrate between features for such system, whereby relatively low the contact stops 13, 13. The spacing of the poles maintenance requirements are involved. N, N from the poles S, S with respect to each Another object is to provide an armature of light other, and to the armature 11 and the thickness 10 weight to facilitate a high speed of vibration. of the armature, will be such that the stop con- A further object is to provide a system of the tacts 13, 13 can be adjusted to limit the travel of above character which is simple and comparativethe armature to a small magnitude. Under this 1y inexpensive to manufacture. condition the armature 11 gives reliable operation l5 These, and further objects, will be apparent and requires only a small force to cause it to move 15 from the following description when considered from one contact to the opposite contact. in connection with the accompanying drawing, in It will be apparent that the weight of the which one embodiment of the invention is illusarmature 11 which is included in the magnetic trated. circuit, is relatively small as compared with usual Referring to the drawing, in which a respective magnetic structures in which the winding is view of the improved system is illustrated, a peraround the armature itself. This permits the use manent magnet 5 is shown of U-shape form. It of a very light armature without increasing the will be understood, however, that this magnet may reluctance of the operating path too much, with be equally well made in any other suitable form. a net increase in the speed of travel and opera.- 5 The permanent magnet 5 terminates in bipolar tion which it is possible to obtain from the magportions or bifurcated pole pieces to introduce a netic structure, as well as an attendant increase slotted portion between poles N, N on one end of in sensitivity, due to the fact that less energy is the magnet, and a like slotted portion between required to move the lighter armature 11. the poles S, S on the other end of the magnet. The poles, or pole pieces, N, N of the perma- 30 These slotted portions are of such depth as to nent magnet 5 have the same polarity, or are 30 substantially isolate the pairs of poles N, S and polarized in the same direction, and the other N S The poles N, N are connected by a yoke poles S, S are polarized in the opposite direction. 6 of magnetic material, and the poles S, S are Hence, the flux produced by the permanent magsimilarly connected by a yoke '7 of like material. net divides into two paths, one path extending The ends of these yokes extend around the poles from the pole N to the pole S, and the'other path and are bent inwardly so that their adjacent terfrom the pole N to the pole S The fluxes in minals lie flush with the adjacent faces of the these two paths are substantially equal and perpoles N, N and S, S respectively. The yokes 6 meate through the armature 11. The armature and 7 are illustrated as being of rectangular foris equally affected by the fluxes in these two paths, 40 mation, and an operating winding 8 is wound and when no current passes through windings 8, 8 40 about the core of each yoke. The yokes are made of the cores of the yokes 6 and "I, the armature of such material that they provide a low relucmay remain in an unbiased positon, or may, if detance in order to permit the windings 8, 8 to sired, be initially biased due to its weight or due set up a high flux density. In order to aid in this to the employment of a spring in either of its two respect, the yoke members 6 and 7 extend around positions, against one of the contact stops 13, 13. 45 the permanent magnet 5, as previously described, When current flows through the windings 8. 8 in so their ends come in close juxtaposition. The the direction indicated by the arrows. temporary windings 8, 8 are shown as being connected in fields will be produced by the electromagnets 6 series, but said windings may be connected with and '7. One of these electromagnets i. e. 6 will the yokes independently of each other, or, if dethen tend to establish a magnetic field so that. 50 sired, the windings 8, 8may be connected in paralthe part of its core nearest the pole N will be lel relation. In the present case it may be asmagnetically south, and that part nearest-the pole sumed that current enters the terminal 9 and N will be magnetically north. The other elecpasses through the serially connected windings tromagnet i. e. '7 will set up a corresponding con- 8, 8 and flows through the output terminal 10 and dition, i. e., the part nearest pole S will be mag- 55 netically north and the part nearest pole S magnetically south. Thus, the magnetic field adja cent the pole N. as well as the magnetic field adjacent the pole S, will be both decreased in strength while the magnetic fields N 1 and S will be correspondingly increased in strength. The magnetic field between the poles N and S will become weaker than the magnetic field between the poles N and 8. Consequently, the armature 11 will be traversed by a greater flux due to its position between the poles N and S than will be traversed through the armature due to its position between the field of the poles N and S. Therefore, the armature will be attracted toward the poles N and S and close the contact 13 on that side of the armature 11. It will be apparent that when the current is reversed through the windings 8, 8 a converse condition to that just outlined will be brought about. The armature 11 will be thus vibrated between the contact stops 13, 13 in accordance with the direction of the applied current.

What is claimed is:

The combination of 'a U-shaped permanent magnet having bifurcated ends which provide bipolar extremities of the same polarity, a yoke of substantially rectangular formation carried by each end of said magnet and having portions cut away to correspond to said bi-polar extremities, an armature mounted on the closed end of said magnet and adapted to vibrate in the space between the bi-polar extremities and cut-away portions of said yokes; and a winding carried by each of said 1 yokes.

PAUL G. EDWARDS. 

